chore: removing migration step as its no longer necessary

[georgewrmarshall]

Explanation

This PR removes the section regarding disabling dependabot alerts and updates from the migration guide documentation, based on organizational requirements discussed in this Slack thread. It was determined that this step is no longer necessary because:

• Dependabot alerts cannot be disabled at the repository level due to new organizational rules.
• Disabling Dependabot alerts would ultimately be redundant, as the repository will be archived after the migration, which will disable Dependabot by default.
• This step was originally intended to prevent confusion due to updates after migration began, but archiving the repository will achieve the same effect once complete.

References

• Related conversation in Slack: Discussion on Dependabot configuration.

[Gudahtt]

LGTM!